The truck mounted brake assembly described herein relates to such an assembly having a single brake cylinder and a separate slack adjuster each mounted between opposing truss type brake beams of a conventional truck mounted brake rigging which applies brake shoe members to the wheels of the rail vehicle.
Truck mounted brake assemblies are well known in the art. For example, U.S. Pat. Nos. 2,958,398, 3,101,814, 3,499,507, and 4,793,446 describe truck mounted brake systems. The first three patents appear to describe dual brake cylinder systems, the latter two of those three apparently incorporate a slack adjustment member in combination with the two brake cylinders. The fourth listed patent appears to describe to a single brake cylinder system with a separate slack adjuster member occupying the general location of one of the previously employed two brake cylinders shown in the prior three patents. This patent, U.S. Pat. No. 4,793,446, further describes another prior art single-cylinder truck mounted brake assembly “shown in U.S. Pat. No. 4,613,016 and comprises, in addition to the brake beams, a force-transfer lever that is pivotally-connected to each brake beam at its midpoint, with the corresponding lever arms of these force-transfer levers being connected to the force-transmitting members. One force-transmitting member comprises a slack adjuster device, such as that disclosed in copending U.S. application Ser. No. 06/714,596. The other force-transmitting member includes a brake cylinder device, the body of which is mounted on one brake beam between the beam tension and compression members adjacent the strut bar, and a connecting rod between the transfer lever arm of the other brake beam and the cylinder body. The brake cylinder piston push rod is connected to the transfer lever arm of the one brake beam.” Slack adjusters are used to take up the rigging slack caused by brake shoe and wheel wear to ensure that the brake cylinder power stroke remains essentially the same length for each operation of the rail vehicle brake system.
Notwithstanding the availability of single cylinder brake assemblies for many years, there are still many older rail vehicles which are equipped with the earlier designed dual brake cylinder truck mounted brake assemblies of the type described above. As a practical manner, usually due to the cost factor, many older rail vehicles are not “upgraded” until it becomes necessary to do so.
In addition to providing single cylinder truck mounted brake assembly for new rail vehicles, it is also desirable to provide for converting existing rail vehicles from the older style dual cylinder brake assemblies to a new a single cylinder brake assembly, such as will be described in more detail below.